Several al-Qaida militants escaped early Monday from a prison in the southern Yemeni port city of Aden, officials said, tunneling their way out in the second such spectacular jailbreak this year.
A prison officer said at least 10 convicts escaped through an up to 130 feet (40 meter) long tunnel, which took the inmates from under the western side of the Aden prison to near a petrol station outside the prison walls.
A security official said 15 militants fled in the prison break, including 12 convicted for the killing of security officials and a bank heist.
The discrepancy in the number of escaped prisoners could not be immediately reconciled. Both officials spoke on condition of anonymity because they were not authorized to speak to the media.
Yemen, the Arab world's poorest nation, has been wrecked by months of political turmoil and unrest. A popular uprising against longtime President Ali Abdullah Saleh's rule _ inspired by other Arab Spring revolts that toppled autocratic rulers in Egypt and Tunisia _ has been met by a fierce government crackdown.
The crackdown triggered widespread defections earlier this year by soldiers and officers who joined the protest movement. Powerful tribes and their armed fighters also turned against Saleh and waged battles against his forces.
Yemen is also home to al-Qaida in the Arabian Peninsula, which the U.S. considers the terrorist network's most active and dangerous offshoot. Islamic militants with links to the group have taken advantage of the country's turmoil to seize control of several towns in southern Yemen.
Yemen has seen spectacular jailbreaks before.
In 2003, 11 al-Qaida militants convicted for the 2000 bombing of the USS Cole, which killed 17 American sailors and injured 39 others, escaped from the Aden prison.
In 2006, 23 al-Qaida militants broke out of a detention facility in Sanaa, including Nasser al-Wahishi, who went on to become the leader of al-Qaida's Yemeni offshoot.
And in June, nearly 60 suspected al-Qaida militants tunneled their way out of a prison in the southern Mukalla city.
Investigations into these breakouts and subsequent trials showed that some prison security officers were involved in helping the convicts flee and several officers have been jailed.